The ATF and FBI have joined an investigation into the bombing of a Minnesota Islamic center before dawn Saturday as a group of Muslim worshippers gathered to pray.

The blast was caused by what the FBI called “an improvised explosive device” that rocked the Dar Al Farooq Center in Bloomington, the Star Tribune reports.

No injuries were reported after the building was heavily damaged at 5:05 a.m.

“The post-blast environment is very detailed,” FBI Special Agent in Charge Richard Thornton said. “You search the wide area in an attempt to find as many components as you can of the device to help us understand how the device was made. That process is substantially complete. … It was an improvised explosive device that was set off early this morning.”

A massive warehouse fire in Oakland, Calif. that killed at least 36 people Friday night was “a potential crime scene,” officials said Monday as the ATF helped investigate what caused the blaze.

Alameda County District Attorney Nancy O’Malley said murder or involuntary manslaughter charges are among the possible consequences of the fire.

“Right now, we have just started our investigation,” she said. “And we owe it to the community, to those who perished in this fire, and those who survived the fire to be methodical, to be thorough, and to take the amount of time it takes to be able to look at every piece of potential evidence. So that if — when we get to that point of making a decision, we know that we’re making the right decision, based on the evidence that we have discovered and has been presented.”

What’s not clear, yet, is whether there is any criminal liability, O’Malley said.

“Right now, we have just started our investigation,” she said. “And we owe it to the community, to those who perished in this fire, and those who survived the fire to be methodical, to be thorough, and to take the amount of time it takes to be able to look at every piece of potential evidence. So that if — when we get to that point of making a decision, we know that we’re making the right decision, based on the evidence that we have discovered and has been presented.”

The ATF was on the scene trying to determine where the fire began. Officials believe the fire started somewhere in the back of the warehouse.

“We are no closer to finding a cause,” said Melinda Drayton, battalion chief for the Oakland Fire Department.

The ATF is investigating the fire-bombing of a local Republican Party office in North Carolina after someone spray-painted anti-GOP rhetoric on a nearby wall early Sunday morning.

Investigators said a molotov cocktail was tossed through a window of the Orange County Republican Party headquarters overnight, causing a fire that damaged the interior of the building before burning out, the Associated Press reports.

Campaign signs, a sofa and the walls were burned.

On an adjacent building was graffiti that read, “Nazi Republicans leave town or else.”

“They are working around the clock. It is a miracle that nobody was killed,” state GOP executive director Dallas Woodhouse said in an interview, calling the fire “political terrorism.”

Hillary Clinton responded on Twitter that the firebombing “is horrific and unacceptable. Very grateful that everyone is safe.”

Donald Trump tweeted, “Animals representing Hillary Clinton and Dems in North Carolina just firebombed our office in Orange County because we are winning.”